Process for producing spun material resembling wool, cotton, or chappe from viscose solutions



Patented Sept. 5, 11922.

air so 51 "res PATE T OFFICE.

PAUL HERMANN MINCK, F PETECRSDORF, GERMANY, ASSIG-NOR, BY MESNEASSIGNMENTS, TO THE CHEMICAL FOUNDATION, INCL, A. CORPORATION OFDELAWARE.

rnocnss FOR PRODUCING SPUN MATERIAL RESEMBLING WOOL, .oor'roN, onGHAP'P'E mom vrscosn SOLUTIONS.

No Drawing.

Application filed May 16, 1919. Serial No. 297,712.

. (GRANTED UNDER THE PROVISIONS 01 THE ACT-0F MARCH 3, 1921, 41 STAT. L,1313.)

To all whom it.;may concern:

Be it known that I, PAUL HERMANN MINoK, a citizen of the free city ofHamburg, residing at Petersdorf, Riesengebirge,

Germany, have invented certain new and useful Improvements in Processesfor Producing Spun Material Resembling Wool, Cotton, or Chappe, fromViscose Solutions (for which I have filed applications in Germany,principal Feb. 22, 1918-; 1st additional Mar. 27, 1918; 2d additionalApril 6, 1918; 3d additional Aug. 15, 1918; Austria, Sept. 5, 1918;Hungary, principal Dec.

5, 1918; 1st additional Dec. 5, 1918; 2d additional Dec. 18, 1918),ofwhich the followin is a specification.

%t is well known that in preparing viscose solutions for the manufactureof artificial to. a very thorough hydration by' means of T alkali lyes,as only after such treatment,

it will, under action of carbon bisulphide be converted in alkalinesolution into a solution sufliciently thin and homogeneous I essary toobtain the proper degree of hydrav tion of the cellulose, and theviscose solution prepared from such hydrated cellulose before it ma mustmature for at least another four days he spun. If spun immediately anabso utely dull, brittle yarn will be obtained, by the highl hydratedcellulose being precipitated in t e coagulating bath in a form soincapable of diffusing that the solvent agents contained in the yarn andviolently decomposing therein, will likewise decompose the wall of thethread.

With a continued maturation of the solution the greater part of thecaustic soda and carbon blsulphide is again separated from the moleculeof the cellulose alkali Xanthogenate, so that it is then possible toundisturb'edly precipitate the cellulose hydrate by aid of suitableprecipitating baths.

The whole process is very expensive and requires much time, asthepreparation of a solution suitable for being spun into artlficial silkwill require about nine days, during whlch time certain temperatureshave to be maintained, a very complicated plant is required for storingthe material and lastly very complicated spinning baths have to beemployed in spinning the solutlons. The cost of manufacture has, indeed,not played any important part in the manufacture of artificial silk,which may be considered as an article de luxe.

In searching to produce a wool-like spun material for which a greatdemand has arisen owing to the scarcity in wool and cotton the inventorproceeded from the assumption that the heretofore employed far reachinghydration of the cellulose is undesirableas only the strength isrequired and a high gloss is of no importance .if the product is to be.used as a substitute for the natural fibres or for the manufacture offilms.

Practical research showed that there exists a suitable minimum in thehydration of the cellulose, at which the latter will, after beingconverted into the Xanthogenate, still be completely dissolved.

The novel feature of the present process consists in that a solid, softand wool-like spun yarn is produced which may serve as a substitute forwool, cotton and chappe, and yarns made therefrom, in particular suchyarns which have the moderate gloss of real silk. This object isobtained by subjecting, when a viscose solution is used, the celluloseemployed for such solution before its treatment with carbon bisulphideand its solution, to a moderate hydration by means of caustic alkaliesso that the threads will not assume the typical high gloss of artificialsilk. Compared to'the latter the new product has the advantage of itsbeing possible to make and spin it in a single day, whereas with theprocess for making artificial silk about nine days are required.

differs from the usual viscose solutions for 1 i the manufacture ofartificial silk by having a small dispersity and a comparatively higherviscosity, which is about three times as high as the usual solutions.

The new spinni material which co tains the cellulose in solution in. avery slightly hydrated form may, contrary to the known viscosesolutions, be spun immediately after its production, 'and will yield anextremelfi strong and soft yarn having a soft, woo ike gloss. This newresult is owing to the peculiar condition of these solutions. Thecoagulation of the threads obtained frame-the highl viscous solutionsproceeds much more slbwly, so that for this purpose spinning bathsprepared from diluted mineral acids may be used, without theotherwiseappearing destruction of the cellulosehydrate precipitated beingobserved. The combination of the xanthogenatewiththe cellulose moleculeis, owlng to themoderate hydration,

probably weaker in the solution and the solvent agents can, in conseuence of the lesser dispersity of the disso ved' cellulose and theresulting higher difi'using capacity of the coagulating thread, moreeasily emerge from the latter before the same is completely solidified.

Example.

100 k0. cellulose are saturated'witli 18% soda lye and thereuponcentrifuged until it contains only two parts (by .weight) of lye to 1part of cellulose. The cellulose is then left onl for 12 hoursapproximately under the by rating action of the alkali, whereupon it istreated with kc. carbon bisulphide and is dissolved in about 1600 ko. 3%soda lye. The thus obtained spinning material may be immediately spun ina.12-15% sulphuric acid bath, and during this spinning it is ofadvantage to afi'ord the threads as long a travel through the bath aspossible,

It has been further found that, particularly in well. opened cellulosethis already greating reduced after-hydration of the pressed out alkalicellulose by a temporary action of moderate heat and air may be entirelyomitted and that in such case the yarn will become still more woollikeand stronger. v

This represents a twofold improvement both as regards the economy of theprocess and the quality of thefinal product.

Also the solutions obtained from such slightly hydrated cellulose. (by abrief dipping merely). may be immediately spun in baths prepared frommineralacids and do not require a maturin period of several days. Theconcentration and len h of the spinning baths may have eonsi erablymesses wider limits as the coagulating roperties of the spun threadswill, with ecreasing hydration of the cellulose become more andmore-favorable.

It has been further observed that the uality of the yarn is improved byreucingthe quantityof carbon bisulphide coming into action and byincreasing the cellulose contents'of the spinnin solutions. It may behere mentioned that t e cellulose may be dipped at the ordinarytemperature, but that for the dissolutionof the cellulose a somewhatlower temperature has to. be maintained, which is preferably maintainedat the same de ee up to the spinning operation, as according to thefeature of the novel process the after maturing, which is required forthe'production of artificial silk threads, is completely omitted.

- Ema/mph.

freed by centrifuging or pressing from the" surplus soda. lye until thecellulose contains not more than two parts (by weight) of lye to onepartof cellulose. The thus obtained alkali cellulose is thereupon carded andimmediatel treated with about 35% carbon bisulphlde (reckoned to 'thedry cellulose) without exposing the latter previously to an otherwiseusual maturation in closed vessels at higher temperatures. Thexanthogenate is then dissolved in about 1200 k0. 4% soda lyeat atemperature of less than 15 cent, whereupon the solution may beimmediately spun in a mineral acid bath. The solution should be storedat-temperatures below 15 cent. as otherwise the maturing of the viscose,which ought to be avoided, will commence.

It has been found that a very small excess of soda lye beyond two partsof the cellulose weight will very' unfavorably influence the quality ofthe viscose solution and the yarn spun-therefrom.

With the present processan excess of water is to be avoided andaccordingly it does not depend so much on obtaining an exact percentageof caustic soda in the cellulose but on the percentage of soda lyerelatively'to the pe'rcentageof active water, 1. e. there must be noexcess of water either chemically or mechanically bound by the Thesmallest excess of water in the reaction'heat necessarily produced bythe treatment with carbon bisulphide, be decomposed or matured, whichshall by all means be prevented according to my new process.

In preparing solutions for the manufacture of artificial silk thisdanger is of no importance, as the hydrated cellulose fibres will absorbthe carbon bisulphide much more readily and the spinningmaterialproduced has to subsequently mature for several days.

Experience has shown that an excess of liquid not bound by the cellulosewill naturally appear as soon as the cellulose contains, relativelytoits weight more. than a 200% aqueous solution of soda. At 200% andless the xanthogenate consists of a crumbling mass, in which agelatinization of the fibre has not yet occurred, so that the abovedescribed disadvantages as regards the solution and the spinning cannotappear.

lmiereas in the manufactureof artificial silk the alkali cellulose hasto be subjectedto storage for several days at temperatures from 20-30"cent., in order that at the further proceedin of the process the typicalhigh gloss of t e spun yarn is obtained, the alkali cellulose shall,according to the present new process, even during the brief periodbetween the dipping and the treatment with carbon bisulphide, not besubjected to temperatures higher than 20, as at higher temperatures adeeper reaching change of the cellulose molecules will immediatelyoccur, which will affect the condition of the viscose solution and thequality of the yarns spun therefrom unfavorably as regards the presentrocess. I

lVhen the stated weight of the lye in the alkali cellulose and thetemperatures are ob served to which the same is exposed until it istreated with carbon bisulphide, the spun material will possess theoriginal properties of the cellulose to an almost full extent. It willcombine a mild woollike gloss with a tensile strength which is 50%higher than that of the highly glossy artificial silk and theconsiderably increased strength in a wet condition is particularlyremarkable. This strength is with the new product about 50% of its drystrength compared to only 30% with artificial silk. The wet strength is,thus, more than 100% greater than with artificial silk.-

In spinning thevabove described new cellulose solutions, it has beenfound that these solutions are not always obtained of the same qualityand that'the yarn spun therefrom will, under circumstances be of alesser strength. Careful investigations have shown that in such casesthe cellulose employed possessed an increased oxidizing capacity, orthat the soda lye was of an -unsuitable quality, containing, namely,some noxious substances, such as common salt to a high percentage.

Instead of the intended, reduced hydration of the cellulose, anoxidation of the cellulose will occur under action of the air, and thisoxidation will result in a more or less weakened yarn. It is thereforenecessary to obviate this danger of an oxidation.

An effective means forthis has been found in a comparatively smallquantity of reduc ing substances which will not disturb the equilibriumof the solutions. Such substances are, for example, the various kinds ofsugar which will burn in sodalye under absorption of oxygen tocarbonicacid. The oxidation threatening the cellulose will, when such means areemployed, afiect only the readily decomposing sugar, whilst the carbonicacid produced will serve as a further. protection for the celluloseagainst oxidizing influences.

These reducing substances may be employed in the dipping bath used forproducing the alkali cellulose; when, however, these baths arerepeatedly used, such. reducing substances will form in them by themofthe finished yarn, an average of about 5% sugar will sufiice, calculatedI to the weight of the dry cellulose. The suitable quantity isdetermined according to thecondition of the cellulose and of the sodalye.

According to the present process, therefore, reducing agents, the actionof which has been accurately recognized and gauged, are employed with anovel viscose solution producing a novel result, consisting "in anoxidation of the cellulose being avoided and a maximum strength of theyarn produced being secured.

E wdmple.

100 ko. dry cellulose are hydrated in the aforesaid manner and thentreated with carbon bisulphide. The xanthogenate thus obtained is thendissolved in an aqueous o lution of caustic soda to which about 5 ko.

sugar have beenv added. The non-matured mass is thereupon spun in bathsprepared from mineral acids. I

I claim:-

1. The process of producing I wool-like threads from cellulose materialswhich comprises treating cellulose with a solution of caustic alkalisuficient to produce incomplete hydration without an excess of water, ata temperature not over 20 (3., transforming the cellulose intoxanthogenate by carbon bi-sulphide, dissolving the xanthogenate in anaqueous solution of caustic alkali of 3% to 5% and spinning the solutionin a mineral acid bath. 7

.2. The process of producing wool-like threads from cellulose materialswhich com-' is prises dipping 100 parts of a cellulose containingmaterial. into a caustic lye of about 18% strength, at a temperature ofabout 18 C. allowing said cellulose containing material to remain insaid lye about three hours, removing said lye from said cellulosecontaining material until it contains about 2 parts of lye to one part oflcellulose; then treating with 35% carbon disulphide, dissolving inabout 1200 parts of an aqueous 2o solution of caustic lye at atemperature less than 15 'C. and spinning in a dilute mineral acid bath.

' 3. The process of producing wool-like threads from cellulose materialswhich com prises dipping 100 parts of cellulose into a soda lye ofabout,18% strength at a temperature 0 f about 18 C. allowing saidcellulose to remain in said lye about three hours, removing said lyefrom said cellulose until it 80 contains about 2 parts of lye to onepart .,of cellulose; then treating wlth carbon disulphide, dissolving inabout 1200 parts of soda lye at a temperature less than 15 C.

- and spinning in a 12% to 15% sulphuric 35 acid bath.

4:; The. process of producing wool-like threads from cellulose materialswhich com prises dipping 100 partsof cellulose into a soda lye of about18% strength at a temper- 4o ature of about 18 'C. allowing saidcellulose naaaeae to remain in said lye about three hours, removing saidlye from said cellulose until it contains about two parts of lye to onepart of cellulose; then treating with 35% carbon disulphide, dissolvingin about 1200 parts of 4% soda 1 e containing a carbohydrate other thancellu ose and spinning in a 12% to 15% sulphuric acd bath.

5. The process of producing wool-like threads from cellulose materialswhich comprises dipping 100 parts of cellulose into a soda lye of about18% strength at a temperature of about 18 0. allowing said cellulose toremain in said lye about three hours, removing said lye from saidcellulose until it contains about two parts of lye to one part ofcellulose; thentreating with 35% carbon disulphide, dissolving in about1200 parts of 4% soda lye containing about 5 parts sugar and spinning ina 12% to 15% sulphuric acid bath.

(LA soft wool-like cellulose thread obtained by treating cellulose withan 18% soda lye at a temperature of about 18 C. removing said lyetherefrom until there is contained therein about two parts lye to onepart cellulose; then treating the 35% carbon disulphide, dissolving in4% soda lye con taining 5 parts sugar, at a temperature less. than 15and finally spinning at a 12% to 15% sulphuric acid bath, said fibresbeing free from a silky lustre and having a tense strength greater thanthat of an artificial silk thread of the same size and material.

lntestimony whereof l have afixed my 75 signature in resence of twowitnesses.

j Pl lUlL HERMANN EMINCK. Witnesses:

KARL Harem Pam, Knuec, JOHANNA Mencannrnm lPoLUs'rmoK.

